During the processing of crude oil by refineries relatively large amounts of energy are required. In addition, a relatively large amount of petroleum coke is produced which contains inorganic compounds which, depending upon the crude oil from which the coke is produced, contains a relatively large percentage of vanadium.
In order to supply a portion of the energy required by the petroleum refineries it has been suggested to gasify the carbon contained in the petroleum coke with steam to produce a combustible gas. Sometimes this gasification reaction is conducted in the present of a gasification catalyst such as an alkali metal salt in order to, inter alia, reduce the steam gasification temperature.
It is also known that vanadium, which is very valuable, can be recovered from the ashes of crude oil and/or petroleum coke. However, such recovery of the vanadium is usually conducted using sulfuric acid to leach the vanadium compounds from the ashes which is relatively expensive and also requires special processing techniques.
It would be very desirable if a process could be developed wherein petroleum coke is gasified to produce a valuable combustible gas and, at the same time, the vanadium contained in said coke is recovered in the resulting inorganic ash by an economical and simple manner.
It is therefore an object of the present invention to gasify petroleum coke with steam, in the presence of an alkali metal gasification catalyst, and recovery the vanadium contained in the resulting inorganic ash by the simple and inexpensive expedient of leaching said inorganic ash in water.
Still a further object of the present invention is to provide a process wherein, during the gasification of carbon with steam in the presence of an alkali metal salt gasification catalyst, there is produced a water soluble vanadate compound which can be separated from a substantial portion of the inorganic ash by placing the inorganic ash in a sufficient amount of water to dissolve the water soluble vanadate compound.
Other objects of the present invention will become apparent from the following detailed description.